Deep vein thrombus starts in the lower legs most of the time. The thrombus progresses up the calf into the knee and thigh. Many physicians don’t treat calf vein thrombus as there is a belief that it is not dangerous. It very rare to have above the knee thrombus without calf vein thrombus (98%). Gastrocnemius vein thrombus is very common and anatomically connects directly into the popliteal vein behind the knee. Some physicians feel that calf veins are too small to harm, these are usually physicians who are not looking at the evidence in real time but just reading the information from a report. Look at this Huge Gastrocnemius Vein!
Thank God the above gastrocnemius vein is patent. The one below was thrombosed from the distal calf to the popliteal vein above the knee
Simply put if you are performing venous ultrasound you must look at the calf veins and muscular calf veins (gastrocnemius and soleal). If you are a doctor you should be treating them.